In Hinduism, each day in a week is dedicated to a particular deity in the Hindu pantheon. Tuesday or Mangalvar is dedicated to Lord Hanuman. Upvaas (fasting) on the day is dedicated to Hanuman and Mangal or Mars. Mangalwar, Tuesday, takes its name from the god Mangal or Mars who rules the day and is considered to be a trouble maker, and the fast is to ward off the harmful effects. Red is the preferred color on the day.

It must be noted here that the Hanuman might not be worshipped on Tuesday in all regions. Some communities might be worshipping some other deity. For example, in South India the day is dedicated to Skanda or Muruga or Kartikeya (Kartik). But generally Tuesday is dedicated to Hanuman.

Mangalvar Vrat is observed by those couples who wish to have a son. Other benefits include happiness in the family. People who believe in astrology observe fast to alleviate the harmful effects associated with the planet mangal or mars.

Those who undertake the fast on Tuesdays only take a single meal. It is a whole day fast. The single meal on the day is usually any food made of wheat and jaggery. Most people observe the fast for 21 Tuesdays without a break.

People wear red colored clothes on the day and offer red flowers to Lord Hanuman.

It is believed that Lord Hanuman will help his devotees in overcoming difficulties in life especially those that arises from the activities of Mangal graha.